Access control gates are well known in the art. In some of the prior art chains or similar flexible lines are lowered or drooped from a position barring access to automotive traffic or the like to a position on the roadway over which the traffic can pass.
For example, U.S. Pat. No. 1,642,875--Fitch et al., Sept. 20, 1927 has a manually operated block and tackle array for raising and lowering a chain barrier. This is not well adapted for motor control and the complex threading of the mechanism provides a ready source of failure by knotting or fraying.
Even earlier U.S. Pat. No. 484,572--Rudert, Oct. 18, 1892 has an underground winch array for engaging chain links to tighten and loosen a single chain line across a roadway in response to rotation of an underground manually driven gear assembly. This is expensive in construction and installation.
A single chain line barrier in U.S. Pat. No. 2,663,103--Ellison, Dec. 22, 1953 is pulled between lowered and raised positions by a hydraulic cylinder mechanism. This patent discloses an automatic control system which opens in response to payment of a toll and which closes automatically as a vehicle leaves the barrier. A very limited range of movement is provided without a very long hydraulic cylinder.
A further chain line barrier is shown in U.S. Pat. No. 1,790,304--House, Jan. 27, 1931 where a lever arm and eccentric pully wheel are rotated manually between a latching and release position for a chain gate barrier array.
There are several deficiencies of such prior art systems however. For example, it has not been heretofore feasible to provide automatic electrically operable barrier gates at unattended country locations where there is no access to power lines, to keep automobile traffic selectively out of farms, cottages, etc.
Significant problems in this respect have not been overcome, since reliable battery operation requires low energy in use to control gate access and need be combined with an appropriate gate barrier. Thus, the flexible line or chain barrier gate is feasible to use, but the prior art mechanisms are not adaptable to the remote electrical operation because high battery drain would not be an acceptable condition and would result in down-time need to recharge and/or replace batteries often and thus would not overcome the lack of available operating power.
Furthermore, it is an object of this invention to attain the improved feature of energy saving and operation solely from solar energy.
When low power battery operation is employed other problems appear that are not recognized or solved in the prior art. For example, the line must be handled in such a way that it is held taut and reasonably high off the ground to produce a substantial barrier deterrant that can be seen readily by a motorist over an automobile hood. Otherwise, the barrier may be broken down forcefully by unauthorized entries.
In the event of such unauthorized entry it is also desirable, even if significant damage is induced to the front end of a vehicle driven through the barrier, there should be no significant damage to the barrier entry system. The prior art provides no effective means for this feature.
Also if a barrier is installed in a limited usage country location it need be simple enough to operate under all conditions encountered with little need for repair or maintenance. Thus, complex chain or flexible line handling mechanisms, which could jam or mishandle the line during the rather large range of movement necessary to drop a line from non-access position generally parallel to the roadway to a position on the roadway which can be driven over, are not tolerable, nor are slowly actuated systems which require more power to move heavy barriers.
Also it is most desirable to provide a reliable and effective system at reasonable cost.
Thus, it is a general objective of this invention to overcome the foregoing disadvantages of the prior art and to have features achieving further advantages such as will be found throughout the following description, drawings and claims.